Arrangements for automatically adjusting correct reference values for yarn faults in electronic yarn cleaners

ABSTRACT

A circuit for controlling the operating parameters of an electronic yarn cleaner arrangement wherein the outputs of the amplifiers of a plurality of yarn cleaners are each connected through a switch and a resistor to a common point which is connected to one input of a comparator, the other input of the comparator being connected to a selectable reference voltage and the output of the comparator being connected to a regulator whose output collectively controls the amplification factor of all of the cleaner amplifiers. An indicating arrangement may also be associated with the comparator to indicate the degree of deviation, if any, from the desired reference.

United States Patent Aeppli 1 Dec. 30, 1975 ARRANGEMENTS FORAUTOMATICALLY 3,048,817 8/1962 Greening 330/130 X JUST CORRECT REFERENCE3,434,065 3/1969 Chu et a1. 330/127 X 3,488,604 1/1970 Smilowitz 1.330/51 X VALUES FOR YARN FAULTS IN ELECTRONIC YARN CLEANERS Kurt Aeppli,Uster, Switzerland Assignee: Zellweger, Ltd., Switzerland Filed: Feb.18, 1972 Appl. No.: 227,509

Inventor:

Foreign Application Priority Data Feb. 19, 1971 Switzerland 2427/71References Cited UNITED STATES PATENTS 2/1950 Harris, Jr. 330/130 XPrimary Examiner-James B. Mullins Attorney, Agent, or FirmCraig &Antonelli 57 ABSTRACT A circuit for controlling the operating parametersof an electronic yarn cleaner arrangement wherein the outputs of theamplifiers of a plurality of yarn cleaners are each connected through aswitch and a resistor to a common point which is connected to one inputof a comparator, the other input of the comparator being connected to aselectable reference voltage and the output of the comparator beingconnected to a regulator whose output collectively controls theamplification factor of all of the cleaner amplifiers. An indicatingarrangement may also be associated with the comparator to indicate thedegree of deviation, if any, from the desired reference.

10 Claims, 11 Drawing Figure TO DETECTOR PORTION OF CLEANER U.S. PatentDec. 30, 1975 $75 5 Lo 2958 @0553 E ARRANGEMENTS FOR AUTOMATICALLYADJUSTING CORRECT REFERENCE VALUES FOR YARN FAULTS IN ELECTRONIC YARNCLEANERS This invention relates to arrangements for automaticallyadjusting and correcting reference values for yarn faults in electronicyarn cleaners.

Electronic yarn cleaners having electromagnetic yarn cutters have beenused to remove blemishes and other defects from yarns during spoolingoperations by severing the yarns. Yarn cleaners are used with textilewinding machines of any type and serve to scan the yarn for uniformityand in the presence of an irregularity, such as constrictions, thickenedportions, slubs, etc., delivers a control signal which is employed forcutting the yarn or for automatically cleaning the yarn at the locationof the irregularity.

Electronic yarn cleaners necessitate a relatively accurate preadjustmentof different parameters if they are to have the required cleaningeffect. These parameters vary in dependence upon the measuring principleapplied; that is, in capacitive yarn cleaners, allowance has to be madefor material and moisture, while in the case of optical yarn cleaners,allowance has to be made for material, color, surface or twist.

In the past, allowance has been made for some of these parameters bypreadjusting those parameters whose effect can be compensated byelectrical values in the yarn cleaner to the original state by means ofdifferent adjusting means in a central apparatus. For example, it ispossible to define a so-called material count which reflects thecomposition of the material and which can be used as a basis topreadjust the yarn cleaner to provide for the proper parameters.

However, a reference value such as this can undergo changes during theoperation of a winding machine equipped with electronic yarn cleaners.Above all, the yarn count is prone to changes of this kind whetherthrough certain fluctuations in count present in a given package orthrough the use during bobbin change of different packages withdifferences in the yarn count. There is also a danger of the operatoromitting to carry out a setting which takes the count of the yarn to beprocessed into consideration with the result that considerablequantities of yarn with wrongly selected reference values may possiblybe wound and cleaned. The effect of this is that the degree of cleaningis either too low, in other words, too few yarn faults are rejected, oralternatively too sharp, in other words, the yarn cleaners respond toeven slight increases in thickness. The result is a yarn that has fartoo many knots.

Accordingly, there is a need to incorporate in the yarn cleanerspresently provided in winding machines an automatic means of adjustingthe yarn count to be processed which replaces manual monitoring andadaptation in a predetermined count range.

The present invention satisfies this need and provides a circuitarrangement for automatically adjusting correct reference values foryarn faults in electronic yarn cleaners, in which the outputs of theamplifiers of at least two yarn cleaners are connected together througha switch and a resistance and are applied to the input of a comparatorwhich acts through a regulating device to change the degree ofamplification of all the yarn cleaners in the sense that the voltagevalues at its input are directed towards a predetermined ideal value.

The comparator generates a reference voltage which corresponds to theparticular reference value and with which the voltage value present atits input is compared. Depending upon the polarity of the differencesignal, a regulator is controlled, increasing or reducing in stages theamplification of the connected yarncleaner amplifiers. The input of thecomparator is preceded with advantage by a resistance-capacitor sectionwhich acts as a low-pass filter and which smooths the basicallyundulating signals arriving from the yarncleaner amplifiers.

In one advantageous embodiment, the circuit arrangement according to theinvention is coupled to an indicator designed to show three phases ofthe input signal, for example, by means of indicating lights, asfollows: (1) When the input signal corresponds to the reference voltagewithin predetermined limits, there is no readjustment of amplificationand a first light signal is illuminated. (2) When the input signal issmaller than the reference voltage, amplification is increased by onestage and a second light signal is illuminated. (3) When the inputsignal is greater than the reference voltage, amplification is reducedby one stage and a third light signal is illuminated.

An embodiment of the invention will now be described by way of examplewith reference to the accompanying drawing which is a schematic circuitdiagram of one form of the invention.

The arrangement illustrated in the drawing includes yarn-cleaneramplifiers l, 1", l" which have inputs connected to the detectionportion of the respective yarn cleaners (not shown) and outputsproviding the voltage values U U U,, connected to the operationalportion of the cleaners (also not shown) and to the switches .2, 2" 2".These switches can be actuated either manually or automatically inconjunction with a mechanism for switching on a winding station. Theswitches 2, 2" 2" connect the outputs of all the amplifiers to a commonpoint 4 through respective resistances 3', 3" 3". The common point 4 isconnected to an adjusting unit 5 in which a capacitor 6 connectedbetween point 6 and ground initially smooths the input signals. Theadjusting unit 5 further includes a comparator 7 and a regulator 8.

A reference voltage which can be preselected by means of an adjustingmember (not shown in detail) is applied to and compared with the inputvoltage in a comparator 7. The adjusting member may take the form of apotentiometer 7' connected to a voltage source and having its adjustabletap connected to the second input of the comparator. The resultingdifference in voltage triggers a regulator 8 which, depending upon thepolarity of the differential signal, transmits to a lead 9 an electricalvoltage value which determines the amplification or gain of theyarn-cleaner amplifiers l, l" I". The regulator 8 can be in the form of,for example, a voltage divider whose tap is driven by a motor to anextent and direction dependent upon the size and polarity of thedifferential signal.

While the specific details of the yarn cleaners with which the presentinvention is associated have not been specifically described andillustrated herein, it should be understood by those of skill in thisart that the invention is applicable to any conventional yarn cleaner,whether operating or capacitive, optical or other known detectionprinciples, which provides a control signal to actuate the operationalportion of the cleaner. The amplifiers I, l" I" are conventionalamplifiers of thetype wherein the amplification factor is adjustable inresponse to.an applied control signal, i.e., a so-called variable'gainamplifier.

The differential signal can be additionally delivered by a lead l0.to anindicator board 11 having, for example, three indicators, such as signallamps l2, l3, and 14, of which oneis provided for correct adjustment, asecond for deviations to one side and .a third for deviations to theother side of the correct adjustment. Instead of or in addition to thesignal lamps, it is also possible to use, for example, an indicatinginstrument in which the particular operational state of all the yarncleaners connected to the point 4 can be recognized from the position ofthe pointer.

The circuit arrangement of the invention operates as follows: After ayarn has been inserted into one-of the yarn cleaners and the windingstation subsequently started up, the switch 2 associated with theparticular yarn .cleaner is closeduntil the comparator 7 has determinedthe difference, if any, between the measured voltage value derived frompoint '4 at the output of the amplifiers and the reference voltage andhas adjusted the regulator'8 accordingly. After this testing operation,the switch 2 is reopened and the winding station continues to runwiththe same degree of amplification to which it has been preadjusted.Only after another yarn has been inserted, whether at the same windingstation or at a different winding station, is monitoring repeatedthrough closure of the switch 2 associated with thatparticular windingstation. From this there is derived the following operationaladvantages- I The amplification of all of the combined yarn cleaneramplifiers is adjusted in accordance with an average value of-thevoltages'which they supply; as a result, each yarn cleaner has an equalinflue'nce'upon the correction of the amplification ofthe respectivecleaners. Thus, serious misadjustment' is prevented in the event offailure of the detecting unit 'of one of the yarn cleaners. 1

lfa yarn differing from those of the other winding stations is wronglywound in one yarn cleaner, the reaction upon the remaining cleaners isslight, and so the sensitivity of the other cleaners remains withintheir required limits. In addition, if by contrast the reference leasttwo yarn cleaners each having a variable gain amplifier providing anoutput control signal, a respective switch and resistance connected inseries to the output of each amplifier and to a common point, comparatormeans for comparing the voltage at said common point with a referencevoltage, and regulating means for regulating the gain of all of saidamplifiers collectively in accordance with the difference between saidreference voltage and the voltage at said common point as provided bysaid comparator means.

2. An arrangement as claimed in claim 1 wherein said comparator'meansincludes adjusting means for selectively adjusting the value of saidreference voltage:

3. An arrangement as claimedjin claim 2,further including a low passfilter connected to said common point to smooth the voltage applied tothe input of said comparator means. v

4. An arrangement as claimed in claim 2 wherein said adjusting meansincludes a potentiometer providing said adjustable reference voltage.

5. An arrangement as claimed in claim 4 wherein said regulating meansincludes a voltage divider having a movable tap providing a regulatingsignal for said amplifiers and 'means for adjusting the position of saidtap in response to theoutput of said comparator.

6. An arrangement as claimed in claim 5, .further including indicatingmeans connected to said comparator for indicating various ranges ofdeviation of the voltage at said common point from said referencevoltage.

7. An arrangement as claimed in claim 6 wherein said indicating meansincludes a pluralityof indicators selectively energized to show theparticular condition of the yarn in relation tothe reference valueadjusted in said comparator means.

r 8. An arrangement as claimed in claim 1 wherein said regulating meansincludes a voltage divider having a movable tap providing a regulatingsignal for said amplifiers and means for adjusting the position of saidtap in response to the output of said comparator.

9. An arrangement'as claimed in claim 1, further including a low passfilter connected to said common point to smooth the voltage applied tothe input of said comparator means.

10. An arrangement as claimed inclaim 1, further including indicatingmeans connected to said comparator for indicating various ranges ofdeviation of the voltage at said common point from said referencevoltage.

1. An arrangement for automatically adjusting and correcting thereference values for yarn faults in electronic yarn cleaners comprising,in combination with at least two yarn cleaners each having a variablegain amplifier providing an output control signal, a respective switchand resistance connected in series to the output of each amplifier andto a common point, comparator means for comparing the voltage at saidcommon point with a reference voltage, and regulating means forregulating the gain of all of said amplifiers collectively in accordancewith the difference between said reference voltage and the voltage atsaid common point as provided by said comparator means.
 2. Anarrangement as claimed in claim 1 wherein said comparator means includesadjusting means for selectively adjusting the value of said referencevoltage.
 3. An arrangement as claimed in claim 2, further including alow pass filter connected to said common point to smooth the voltageapplied to the input of said comparator means.
 4. An arrangement asclaimed in claim 2 wherein said adjusting means includes a potentiometerproviding said adjustable reference voltage.
 5. An arrangement asclaimed in claim 4 wherein said regulating means iNcludes a voltagedivider having a movable tap providing a regulating signal for saidamplifiers and means for adjusting the position of said tap in responseto the output of said comparator.
 6. An arrangement as claimed in claim5, further including indicating means connected to said comparator forindicating various ranges of deviation of the voltage at said commonpoint from said reference voltage.
 7. An arrangement as claimed in claim6 wherein said indicating means includes a plurality of indicatorsselectively energized to show the particular condition of the yarn inrelation to the reference value adjusted in said comparator means.
 8. Anarrangement as claimed in claim 1 wherein said regulating means includesa voltage divider having a movable tap providing a regulating signal forsaid amplifiers and means for adjusting the position of said tap inresponse to the output of said comparator.
 9. An arrangement as claimedin claim 1, further including a low pass filter connected to said commonpoint to smooth the voltage applied to the input of said comparatormeans.
 10. An arrangement as claimed in claim 1, further includingindicating means connected to said comparator for indicating variousranges of deviation of the voltage at said common point from saidreference voltage.